登录界面 beta版

1.MainActivity.java

package com.example.administrator.myapplication;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    EditText et_usercode;
    EditText et_password;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        et_usercode=(EditText)findViewById(R.id.et_usercode);
        et_password=(EditText)findViewById(R.id.et_password);
    }
    //view 代表事件发起者
    public void bt1_onclick(View v)
    {
        //带返回的打开 注册Acivity

        //第一步:构造意图

        Intent intent = new Intent(this,zhuceActivity.class);

        startActivityForResult(intent,1);
    }
    //成员变量
    String usercode;
    String username;
    String password;

    //重写处理返回信息的回调方法

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        //处理返回信息
        //1-判断请求码
        if (requestCode==1)
        {
            //2-判断结果码
            if (resultCode==RESULT_OK)
            {
                //接收返回的注册信息
                usercode = data.getStringExtra("usercode");
                username = data.getStringExtra("username");
                password = data.getStringExtra("userpassword");
            }

        }

    }

    //登录的方法

    public void bt2_onclick(View v)
    {
        //1.取得填写信息
        String uc = et_usercode.getText().toString();
        String pw = et_password.getText().toString();

        // 2.判断是否正确填写
        if (uc.trim().length()==0||pw.trim().length()==0)
        {
            Toast.makeText(MainActivity.this, "用户代码和密码不能为空", Toast.LENGTH_LONG).show();

            return;
        }
        // 3.判断有没有注册信息
        //1-没有找到注册信息 2-填写的用户信息尚未注册
        if (usercode ==null||(usercode !=null && !usercode.equals(uc)))
        {
            Toast.makeText(MainActivity.this, "用户未注册", Toast.LENGTH_LONG).show();

            return;
        }
        // 4.注册信息与登录信息是否匹配

        if (!password.equals(pw))
        {
            Toast.makeText(MainActivity.this, "密码错误", Toast.LENGTH_LONG).show();

            return;
        }
        else
        {
            //可以登录系统
            Toast.makeText(MainActivity.this, "用户验证成功", Toast.LENGTH_LONG).show();

            //跳转到主界面
            startActivity(new Intent(this,TestActivity.class));
        }
    }
}

2.Actvitymain.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.administrator.myapplication.MainActivity"
    android:orientation="vertical">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="用户代码"
        android:id="@+id/et_usercode"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="密码"
        android:id="@+id/et_password"
        android:inputType="textPassword"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="登录"
            android:onClick="bt2_onclick"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="注册"
            android:onClick="bt1_onclick"/>
    </LinearLayout>
</LinearLayout>

3.zhuceActivity.xml

package com.example.administrator.myapplication;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class zhuceActivity extends AppCompatActivity {
    EditText et_usercode1;
    EditText et_password1;
    EditText et_username1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_zhuce);

        et_usercode1 = (EditText)findViewById(R.id.et_usercode_1);
        et_password1 = (EditText)findViewById(R.id.et_password_1);
        et_username1 = (EditText)findViewById(R.id.et_username_1);
    }
    //view 代表事件发起
    public void bt1_onclick(View v)
    {
        //返回注册信息
        //用户代码
        String usercode = et_usercode1.getText().toString();
        if(usercode==null||usercode.trim().length()==0)
        {
            Toast.makeText(zhuceActivity.this, "请正确填写用户代码", Toast.LENGTH_LONG).show();

            return;
        }
        String username = et_username1.getText().toString();
        if(username==null||username.trim().length()==0)
        {
            Toast.makeText(zhuceActivity.this, "请正确填写用户名称", Toast.LENGTH_LONG).show();

            return;
        }
        String password = et_password1.getText().toString();
        if(password==null||password.trim().length()==0)
        {
            Toast.makeText(zhuceActivity.this, "请正确填写用户密码", Toast.LENGTH_LONG).show();

            return;
        }

        Intent intent = new Intent();

        intent.putExtra("usercode",usercode);
        intent.putExtra("username",username);
        intent.putExtra("password",password);

        //设置返回信息:1-结果码;2-携带数据的Intent.
        setResult(RESULT_OK,intent);

        finish();
    }

    public void bt2_onclick(View v)
    {
        setResult(RESULT_CANCELED, null);

        finish();
    }
}

4.activity_zhuce.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.administrator.myapplication.zhuceActivity">
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="用户代码"
        android:id="@+id/et_usercode_1"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="用户名称"
        android:id="@+id/et_username_1"
        android:layout_below="@+id/et_usercode_1"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="登录密码"
        android:id="@+id/et_password_1"
        android:layout_below="@+id/et_username_1"
        android:inputType="textPassword"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true">
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="取消"
            android:onClick="bt2_onclick"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="确定"
            android:onClick="bt1_onclick"/>
    </LinearLayout>
</RelativeLayout>

呵呵,导致程序无法运行的错误啊!